Bluetooth, babies, and bathwater

The Bluetooth Special Interest Group has just released some of the details of Bluetooth 5.0, the latest version of its Internet of Things wireless protocol, to be released to developers later this year. Bluetooth is one of the major contenders in an IoT market that ABI Research projects will grow to over 40 billion devices by 2022. The SIG is also working on a separate follow-on mesh architecture that it thinks will give it an edge over competitive specs such as ZigBee and Thread.

Version 5 enhancements cover the whole range of apps where Bluetooth plays a role: the key element in the beaconing and location services built into most mobile phones; an easy-use personal networking tool that allows people to use their smartphones to access and control devices near them or in their local environment; and a means by which to provide users - but more importantly, the companies that provide the wireless IoT devices - with access and control of literally thousands of devices in a home or a building.

Among the improvements are such things as doubling the peak data rates from 1 to 2 Mbits/second and quadrupling its range from 30 to 100 meters, all with the aim of moving away from the traditional Bluetooth app-paired-to-device model to a connectionless IoT similar to that employed on IoT protocols such as ZigBee and Thread.

"The ubiquitous presence of Bluetooth in the mobile space is a key driver for the technology," said Andrew Zagani, industry analyst at ABIResearch. “Beacons are arguably the most obvious application related directly to its presence here. The arrival of Bluetooth 5 with its 8X increased broadcast messaging capacity will enhance its opportunities further.”

Zagani said that in terms of applications such as the smart home, a key selling point will be that Bluetooth as it is currently configured does not require a separate gateway to be purchased but can use an existing smartphone or tablet device to control smart home devices.

"This removes a significant barrier to adoption and reduces the complexity and cost of developing separate gateway devices. Again, the increased range from Bluetooth 5 will also allow for greater coverage, enabling control of smart devices throughout the whole home and even outdoor applications."

But much of the success of Bluetooth in the IoT and mobile beacon markets will depend on yet another enhancement: its Smart Mesh specification, and whether it can bring the advantages of that approach in future markets without affecting the use of the protocol in present beaconing and personal area networking apps.

The Bluetooth Smart Mesh specification is expected to be announced separately by the end of 2016. If the Bluetooth Special Interest Group is successful in its aims, ABI Research projects that its use in building smart home devices will grow by over 75 percent between 2016 and 2021 (see Figure).

Figure. ABI Research projects that Bluetooth device shipments will total over five billion units by 2021. While its use for beaconing in smartphones will remain the largest segment, significant growth is expected for the connected home, which could at least double. (Source: ABI Research)

Enough details have emerged about Smart Mesh to get companies who are members of the Bluetooth SIG excited about the possibilities. For one thing it greatly expands the area and number of nodes it can support and will also allow implementation of smart apps that take advantage of the data shared across nodes. The mesh will use a flooding approach that is supposed to be easier to implement than the IEEE 802.15.4-based ZigBee routing scheme based on Ad hoc On-demand Distance Vector (AODV). However, it makes some compromises in terms of latency compared to the alternatives in order to conserve energy.

"The Bluetooth SIG’s adoption of mesh is primarily driven by the needs of the IoT market," said Adnan Nishat, marketing manager for Bluetooth SoCs at Silicon Laboratories. "Many of today’s IoT applications (connected home, building & industrial automation, lighting, smart meters and many others) require control, automation, and co-ordination between a large number of nodes."

He said point-to-point solutions (and multi-hop alternatives such as Bluetooth scatternets) were the first attempts but are far from sufficient. “Home devices require reliable and robust communication with very low latency. The move into mesh by the Bluetooth SIG is to provide this capability.”